Surviving in extreme cold

With record low temperatures sweeping across North America people are having to face weather conditions that they may not have encountered before. It’s not impossible to survive such conditions, the Evenk people of Siberia, and the Inuit of Northern Canada manage perfectly fine in conditions colder than the United States is currently experiencing. The difference is they are born to it, and generations of knowledge have been passed down to them regarding how to deal with extreme cold.

Hypothermia

Hypothermia occurs when a person’s body temperature drops below 35°C (95°F). Normal body temperature is around 37°C (98.6°F). It can quickly become life threatening and should be treated as a medical emergency. It’s usually caused by being in a cold environment and can be triggered by a combination of things – such as being outdoors in cold conditions for a long time, living in a poorly heated house or falling into cold water.

People who are particularly at risk are those who are elderly or ill and are unable to move around easily to generate heat. Babies are also more prone to developing hypothermia because their bodies’ ability to regulate their temperature isn’t fully developed.

However, it is not just babies and elderly people who develop hypothermia. Anyone who spends long periods outside during the winter without wearing appropriate warm clothing can also be at risk, particularly after drinking large amounts of alcohol.

For example, there have been several cases in recent years of young people developing hypothermia while making their way home drunk after a night out. They were lightly clothed and lost their way home, only to be discovered dead, or close to death, with severe hypothermia.

The signs of hypothermia vary depending on how low a person’s temperature has dropped.

Mild hypothermia

If someone has mild hypothermia (generally with a body temperature of 32-35˚C), the symptoms aren’t always obvious but they can include:

constant shivering

tiredness

low energy

cold or pale skin

fast breathing (hyperventilation)

Moderate hypothermia

Moderate cases of hypothermia (generally with a body temperature of 28-32˚C) can include symptoms such as:

being unable to think or pay attention

confusion

loss of judgement and reasoning (someone with hypothermia may decide to remove clothing despite being very cold)

difficulty moving around

loss of co-ordination

drowsiness

slurred speech

slow, shallow breathing (hypoventilation)

People with a body temperature of 32˚C or lower will usually stop shivering completely. This is a sign that their condition is deteriorating, and emergency medical help is required.

Severe hypothermia

The symptoms of severe hypothermia (a body temperature of below 28˚C) can include:

unconsciousness

shallow or no breathing

weak, irregular or no pulse

dilated pupils

Someone with severe hypothermia may appear to be dead. However, under these circumstances the individual must be taken to hospital to determine whether they have died, or if they are in a state of severe hypothermia. Medical treatment can still be used to resuscitate people with severe hypothermia, although it is often fatal. Babies with hypothermia may look healthy, but their skin will feel cold. They may also be limp, unusually quiet and refuse to feed.

Blood

We are all aware that heavy duty snow shovelling can cause a person to keel over with a heart attack, but this is not the main cause of heart attacks during cold weather. Heart attack and strokes, or to give them their proper names, cardiac arrest and cerebo-vascular accident are responsible for thousands of cold weather deaths each year. They are listed on the statistics as exactly what they are, but as a heart or brain does not have ‘packed up due to cold weather’ stamped on it at autopsy it’s hard to absolutely say the death was caused by the weather.

These two conditions are entirely different but they do have one thing in common…blood. Both conditions are caused by a clotting of, or restriction of, the flow of blood through an organ, namely the heart and the brain, and this is where blood supply comes in.

Although blood is a liquid, it’s viscous, it has a stickiness to it that some fluids, such as water, don’t have. Like motor oil, blood becomes more viscous if its left in the open air, and it becomes more viscous when it is cooled, and less viscous when it’s warmed. So, when it’s trundling around in your blood vessels, for the most part all is well, it’s warm and fluid and goes on it’s way doing it’s thing.

In some parts of your body blood vessels are far nearer the surface than you might think, look at the inside of your wrists, your jugular vein that you may see pulsing in your neck, the veins visible at your temples, and in the case of newborns under the thin skin of their scalp. Here the blood dissipates heat far more readily than it does from other parts of your body. When it cools, it becomes a little stickier, a little more viscous. Cool it further still, like on a really cold day, and it becomes even more viscous. Sticky blood cells stick together and form tiny clumps, which turn into bigger clumps quite quickly, certainly within a couple of hours.

If that clot breaks free and makes it to the heart a cardiac arrest be the result. If it makes it to the brain a stroke will result, and if it makes it to the lungs a life threatening pulmonary embolism is likely to occur.

Frostbite

All cells contain fluid, and when that fluid freezes it expands, just like the water in an ice cube tray expands in your freezer. This causes the cell membrane to burst, and the cell dies. This is why frostbit victims have blackened areas of skin, the cells in that area are dead, and they can never be regenerated. If the dead area is dry, such as a frostbitten finger, it will eventually drop off with very little risk of infection. However, if the area is wet gas or wet gangrene develops and the affected area needs to be excised, cut out, or amputated if a digit or limb is involved.

Needless to say, frostbite is to be avoided at all costs. This is relatively easy to do if you are prepared with the right clothing, equipment and mindset. Clothing should be layered, with a wicking layer at the base that won’t leave moisture on the skin, and a tightly woven outer layer. Mittens are warmer than gloves. Hand or foot warmers can be placed inside a glove or inside a boot, though these may not heat the tips of fingers or toes.

Goggles or glasses will protect the eye area though eyeballs themselves are unlikely to be damaged by extreme cold. Eyelashes only freeze when wet.

Frostbite increases with the wind chill. The stronger the wind, the higher the windchill.

Image:NOAA

Earrings and piercings that are exposed to the weather should be removed as the metal cools rapidly and can damage the skin it is touching. The tops of metal zippers should not be allowed to touch the skin.

If you are in a vehicle stay there.

Vehicles

Vehicles should have a full tank before you set off in winter. Setting off with a quarter of a tank of fuel is downright stupid and could well cost you and any passengers with you, your life.

Staying in your vehicle is usually the best policy. Even if you have the right clothing there are many dangers, not least getting lost if you are in an unfamiliar area. Snow drifts, hidden obstacles and exhaustion can end your life quickly if you make a mistake. Every year people die who could have survived if they had stayed put.

Tie something bright to the car aerial so that you can be seen if the snow piles up around you and try and keep the front and back windscreens clear if possible. Not only will this allow rescuers to see any light from inside the car but it helps you feel less isolated. Snow is a great insulator and allowing it to build up on the roof will retain heat inside the car.

The old adage is that you should run the engine for five to ten minutes an hour to heat the car. In many situations that won’t be long enough to even take the chill off. How long you run the engine for depends on how much fuel you have and the situation you are in. On a main road where rescue services are visible, even if they are a couple of miles up the road you may be able to keep the car idling until your turn to be rescued comes. If you are in the middle of nowhere and rescue is going to be many hours or even a couple of days before reaching you keeping the engine running may be a luxury you cannot afford.

If you are travelling in winter you should ALWAYS have supplies with you. High energy snacks, trail mix, biscuits or sandwiches, whatever you like is fine, but it’s no good at all unless you have it with you. You should also carry at least three times more water/drinks than you anticipate needing.

Your car kit should also include: (per person)

A torch/flashlight

A blanket or quilt

Spare socks and rubber boots

A hat

A Spare sweater

Prescription medications

Sunglasses. These will prevent glare if you HAVE to leave the vehicle in daylight.

A mylar/space blanket

A fully stocked get home bag, and a charged mobile/cell phone with the items above as back ups would be the ideal. A mountain rescue leader told me that carrying a disposable barbeque and a bicycle inner tube is a good idea. The inner tube smokes like hell and makes a good signal if you are in a remote area.

If you are staying in the car you need to make sure the exhaust stays free of snow and ice otherwise gases can be forced back into the car. You can’t smell, see or taste carbon monoxide, and it can kill very quickly in such a small enclosed space. Keep a window cracked to be sure that any gases can escape. If you are able to move the car back and forth a foot or so in both directions it leaves a gap at each end to allow gases to escape. You should still get out and physically check every time you are going to start the engine and at regular intervals if you are keeping the engine running.

In a building

Hopefully the building you are in will be your home, and of course you home is prepared for the worst possible weather. You have food and water stored, and an alternative form of lighting and heat ready in case the grid fails.

If you are in a building that isn’t home then your options are far more limited. Fill containers from drinking water taps so if the grid fails you will have something to drink. Find an area away from windows to set up your ‘camp’. Heat will be easily lost in large offices, factories and classrooms so getting an area comfortable should be your first priority after securing your water supply.

Once you have decided where you are going to camp move furniture or equipment to create makeshift walls. Find something to go over the top. Depending on where you are this might be a tarp, office cubicle screen or even cardboard. You are basically building a room within a room to retain heat. A well built shelter can have temperatures a full 20*C warmer than the air outside the shelter.

Once the structure is built find anything you can to put inside to increase your heat retention and comfort. Cushions, books, cardboard, newspaper, blankets, anything that’s to hand will have to do, and it’s surprising just what you can find, and what you can do with it when you have to.

Shelter sorted food is your next priority. If the building has a staff canteen or dining room there should be no issue. If not vending machines, coffee rooms, desk drawers and lockers can yield a surprising amount of snacks. Once again if you have a get home bag with you the contents will be of use even though the conditions mean you are not using it for it’s original purpose.

Setting out on foot

It shouldn’t be underestimated how hard it is to walk through snow or to tackle ice. Getting injured, getting lost or collapsing through sheer exhaustion are all possibilities. If you don’t have the right clothing hypothermia and frostbite cut your chances even further.

Unless you know where you are in relation to where you want to be, setting out on foot should be your last choice. Seriously consider if you are fit enough to get home in the conditions you are facing.

Extreme cold is one of those situations that can get out of hand very quickly. Rather an uncomfortable night in the car or stuck at work than someone finding your frozen body in a snow drift a week later.

Lizzie Bennett retired from her job as a senior operating department practitioner in the UK earlier this year. Her field was trauma and accident and emergency and she has served on major catastrophe teams around the UK. Lizzie publishes Underground Medic on the topic of preparedness.